What controls the defrost of the evap coils, I have a S/N T27208-1 M/N 2020FRM On ocasion the two evap coils ice up, My charge is correct, My Evap fans all run. I see a two wire brown leads that go to a small control that looks like a Klixon that clips on two the back of the coil. Is this the control that controls the Defrost?

On Hoshizaki freezers, it has several items that can cause this. Check to see if the heater in the evap are heating up when in defrost. Older machine can force a defrost by just unplug and then plug back in to outlet to do this. There is a "Klixon" type thermostat that disconnects the heaters in case of an overheating condition. These go bad fairly often. Make sure the door closes and seals. Be sure not to do anything that hampers air flow over the evap.

Extend the defrost time so the water escapes before refreezing or add an extra heater to the drain

hi... is the evap fan motor running in the freezer ? if it is then check the the evap coils if it is completely frosted then u need to check the defrost timer .if that is good then check the defrost limiter that is on the evap coils and if that is good then u got a bad defrost heater. now if there is frost only on the bottom or top of evap coils u may have sealed sys problem if u got an ? feel free to write me..

if the evap fan is not turning try to turn it by hand a few times then start you freezer if it does not turn it needs to be replaced.make sure there is no ice build up on the evap coils.alos check the continuity of the defrost heater below the evap coils.once you het teh fan replace your unit should cool down to the proper temps.

Since your symtom is general, I'll answer as such.

An air leak due to doors not sealing can cause general icing. A defrost cycle that is too long can cause icing in areas other than the evap. A defrost cycle that is too short can cause evap icing. Intermittent problem with the evap fan. Overloading the unit with too much product can restrict air flow and cause icing. Door not closing due to spring loaded door closing hinge not working correctly.
I'd start with some of these suggestions to see if we can get you in a direction.
Your freezer should be able to handle a minus 5 to 10 degrees, generally speaking.

Can't locate specific manual for your product but sounds like a defrost problem.
Unit should defrost on a regular basis. Usually controlled by a timer. It should turn refrigeration system off, including fans, and turn on heaters to clear any frost or ice on the evap coils. Cycle varies on usage. Look for timer and see if it is running. Make a mark on it and give it an hour and check again to see if it has moved.
Hope this gets you started.

The defrost cycle is a set time. I would suggest cleaning the evaporator so it has less chance to hang up in the trays.

If you are seeing droplets on the ceiling and runs down the back wall behind the evap I got a reason.
The unit is probably staying in defrost too long. The frost on the evap melts and some of it drips onto the heater elements. This turns it into steam which rises and hits the cold, metal ceiling. The steam condensates into droplets and whent the system comes back on, they freeze. This can also cause the runs down the back wall too. Seen this happen alot. Check to see that the fan delay is working, It causes the evap fans to come on only after the evap chills down to about 20 degrees after a defrost ends.
Hope this helps ya.

The coil in the conditioned space is called the evaporator.
If the water droplets are forming on the ceiling around the evap, it is due, most likely, to the defrost cycle being too long.
Defrost cycle: compressor stops, evap fans stop, electric heaters in the evap come on to clear any ice/ frost on evap fins/ coil.
The ice/ frost melts and some of it turns into vapor. As it hits the cold ceiling surface, it condensates into water droplets. Defrost cycle could be too long. Usually 4 time aday and no longer than 30 minutes should be enough unless there is high humidity.
There could be another cause.
Normally, after a defrost cycle terminates, the evap fans do not come on, due to a delay control. This prevents circulating warm are due to the heaters. The compressor comes on and cools the evap down to, usually 20 degrees or so, and then the fans come on. What could be happening is, the fans are coming on too early and blowing the water driplet off the evap and onto the back wall of the unit.
A third item, is to be sure that the condensate drain is "P" trapped. The prevents warm, outside air from being drawn in and causing exess frost build up, thus excess water and vapor.

Good luck and hope this helps

Freezers have a sensor that is referred to as a "Fan Delay/Defrost Terminator". It senses the temp during the defrost cycle. Usually, when the evap temp reaches about 50 degrees, there should not be any frost or ice on it. This device terminates the defrost cycle. It also keeps the fans off so warm air is not circulated. When the evap gets to about 20 degress or so, the sensor switches on the evap fans. If the fans are not coming on, either the sensor is bad or the evap is not reaching the proper temp to cause the sensor to turn on the fans.

Hope is helps to clear up some things and point you in a direction as to what might be going on.